@article{26244155e5a94b06af66a97478d9f4e1,

title = "Search for muoproduction of X(3872) at COMPASS and indication of a new state X˜(3872)",

abstract = "We have searched for exclusive production of exotic charmonia in the reaction μ+N→μ+(J/ψπ+π−)π±N′ using COMPASS data collected with incoming muons of 160 GeV/c and 200 GeV/c momentum. In the J/ψπ+π− mass distribution we observe a signal with a statistical significance of 4.1 σ. Its mass and width are consistent with those of the X(3872). The shape of the π+π− mass distribution from the observed decay into J/ψπ+π− shows disagreement with previous observations for X(3872). The observed signal may be interpreted as a possible evidence of a new charmonium state. It could be associated with a neutral partner of X(3872) with C=−1 predicted by a tetraquark model. The product of cross section and branching fraction of the decay of the observed state into J/ψπ+π− is determined to be 71±28(stat)±39(syst) pb.",

keywords = "COMPASS, Exotic charmonia, Photoproduction, Tetraquark, X(3872)",

author = "{COMPASS Collaboration} and M. Aghasyan and R. Akhunzyanov and Alexeev, {M. G.} and Alexeev, {G. D.} and A. Amoroso and V. Andrieux and Anfimov, {N. V.} and V. Anosov and A. Antoshkin and K. Augsten and W. Augustyniak and A. Austregesilo and Azevedo, {C. D.R.} and B. Bade{\l}ek and F. Balestra and M. Ball and J. Barth and R. Beck and Y. Bedfer and J. Bernhard and K. Bicker and Bielert, {E. R.} and R. Birsa and M. Bodlak and P. Bordalo and F. Bradamante and A. Bressan and M. B{\"u}chele and Burtsev, {V. E.} and Chang, {W. C.} and C. Chatterjee and M. Chiosso and I. Choi and Chumakov, {A. G.} and Chung, {S. U.} and A. Cicuttin and Crespo, {M. L.} and {Dalla Torre}, S. and Dasgupta, {S. S.} and S. Dasgupta and Denisov, {O. Yu} and L. Dhara and Donskov, {S. V.} and N. Doshita and Ch Dreisbach and W. D{\"u}nnweber and Dusaev, {R. R.} and M. Dziewiecki and A. Efremov and J. Lichtenstadt",

note = "Publisher Copyright: {\textcopyright} 2018 The Author",

year = "2018",

month = aug,

day = "10",

doi = "10.1016/j.physletb.2018.07.008",

language = "אנגלית",

volume = "783",

pages = "334--340",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier",

}